The chancellor also brushed off criticism that she is losing authority among conservatives.

German Chancellor Angela Merkel on Sunday defended "painful" concessions she has made to the Social Democrats (SPD) to secure a fourth term and said growing criticism among her conservatives was not a sign that her authority was waning.

The SPD's traditional left-wing youth organization, Jusos, have opposed a coalition government with the Christian Democrats, and called for reform within the party.

Germany will no longer lecture other European countries over their economies, the next finance minister of the eurozone's richest nation said on February 10. The coalition deal also saw the previously CDU-held Interior Ministry head to the CSU, where party leader Horst Seehofer will reportedly take the lead.

The governor of Schleswig-Holstein state, Daniel Guenther, said earlier in daily Die Welt that "we need new faces" in the Cabinet.

"We sure did pay a price for a stable government", Merkel said.

With many in the CDU unhappy about the loss of the key Finance Ministry, previously headed by European Union austerity advocate Wolfgang Schäuble, Merkel said the criticism was not a sign that her authority in the party was declining.

"The transition to the post-Merkel era has begun", judged the Sueddeutsche Zeitung daily, which added that Dr Merkel's power was waning and "a unsafe mood" was starting to spread within her CDU.

"We shouldn't only talk about how we want to shape the next four years in Germany but also what the CDU will stand for in future, which topics we can win elections with in the next 10 years and people go along with topics", he said.

The embattled leader of Germany's Social Democrats (SPD) abruptly gave up plans on Friday to become its next foreign minister, hoping to shore up support among SPD members for a new coalition with Angela Merkel's conservatives. The CDU has six ministerial posts to fill. The results will be announced on March 4, according to party officials.

Senior figures of Social Democratic Party (SPD), including the current Foreign Minister Sigmar Gabriel, have publicly criticized Schulz and accused him of not keeping his promises.

Merkel's standing in her party was weakened following last September's general election that saw the far-right Alternative for Germany (AfD) snag votes away from all of Germany's major parties.